As an alternative to traditional circuit-switched networks, voice communications, for example, may be routed over packet-switched networks like the Internet. Due to the fact that the Internet is not subject to the same international regulations as are traditional telephone networks, routing voice communications over the Internet tends to be less expensive. Additionally, a voice communication routed over a packet-switched network may require less bandwidth than a voice communication placed over a circuit-switched network like a traditional telephone network. Packet-switched networks like the internet protocol (IP)-based Internet, Intranets, and Asynchronous Transfer Mode (ATM) networks handle bursty data more efficiently than circuit-switched networks because of statistical multiplexing of the packet streams. However, statistical variations of traffic intensity often lead to congestion that results in excessive delays and loss of packets, thereby significantly reducing the quality level of real-time voice communications.
One problem with sending packetized voice over packet-switched networks are the delays associated with channel reallocation. Packet delays above a certain level (e.g., 100–300 mS) are generally found to be annoying for voice conversations. As a result, some networks supporting Voice-over-Packet (VoP) impose a maximum delay requirement of 100 milliseconds (mS). One critical point in the design for such a requirement is the onset of a speech spurt (i.e., when a user starts to speak after a pause or delay) when speech packets are initially generated. Unlike conventional circuit-switched networks, packet-switched networks may not have a dedicated channel ready and available to immediately transfer the packet stream. In conventional packet-switched networks, a media access control device may be employed to reallocate an existing channel and grant access to the channel for the voice packet stream. This channel allocation/reallocation process involves signaling between the various network elements and takes time that can easily exceed an acceptable delay for voice communications as well as the maximum delay requirement imposed on a packet-switched network for voice communication. The channel allocation/reallocation time may become significant especially when existing packet streams have at least as great of a quality of service requirement which may prevent reallocation of their channels. Packet-switched networks have employed partial loading of the access medium (e.g., by reserving a channel) to always allow some capacity for the initial speech onset to meet delay requirements. However partial loading consumes bandwidth because the reserved capacity is unused when no speech packets are being transferred.
Thus there is a general need for an improved method and system for the communication of voice over a packet-switched network. There is also a need for a method and system for communicating voice over a packet-switched network that more efficiently utilizes network resources. There is also a need for a method and system for communicating voice over a packet-switched network that may increase network capacity.